Portable device using passive sensor for initiating touchless gesture control

ABSTRACT

A portable device ( 100 ) comprising a controller ( 210 ), a memory ( 240 ), a camera ( 160 ) and a passive proximity sensor ( 170 ). The controller being configured for receiving input from said passive proximity sensor ( 170 ) indicating a light environment in front of the passive proximity sensor ( 170 ) detecting a change in light environment, determining a light pattern (P) of changes in light environment, determining if the light pattern (P) matches a stored initiating pattern, which is stored in the memory ( 240 ), and if so, accepting the light pattern (P) and in response thereto activating the camera ( 160 ), identifying an object (H) in front of the camera ( 160 ) and tracking the object (H) thereby enabling touchless gesture control of the portable device ( 100 ), characterized in that the passive proximity sensor is an ambient light sensor and the light pattern consists of a series of changes between dark and light (dark is light below a threshold, light is light above a second threshold).

TECHNICAL FIELD

This application relates to a method, a computer-readable medium and aportable device, such as a mobile communications terminal, having apassive sensor and utilizing the passive sensor for initiating touchlessgesture control.

BACKGROUND

Touchless gesture control based on camera capture requires that thecamera is either always turned on and continuously analyses gestures infront of the camera to determine if the gesture is for controlling thedevice or for another purpose. Alternatively the device is manuallyturned on to receive touchless input.

If the camera is always switched on it draws a lot of power, which ishighly unsuitable for a portable device, such as a mobile communicationsterminal for example a smartphone or a tablet computer, running onbattery power. It is also damaging to the environment as power is usedeven when not necessarily needed.

To overcome these problems, some portable devices enable the user tomanually switch on the camera when needed. This requires manual hands-onoperation which is in contrast to the concept of touchless interaction.

There is thus a need for an improved manner of initiating touchlesscontrol that does not consume power and which is in line with touchlesscontrol.

SUMMARY

The inventors of the present invention have realized, after inventiveand insightful reasoning that by utilizing a passive light environmentsensor, such as an ambient light sensor or a passive proximity sensor,it is possible to indirectly detect a gesture.

Even though the passive light environment sensor is not able or arrangedto detect an object performing a gesture, the inventors have realizedthe simple solution to utilize such a passive light environment sensorto indirectly detect the gesture. Since such sensors are often alreadyarranged in portable devices such as a mobile communications terminal,the invention disclosed herein may beneficially be used as a softwaresolution for already existing hardware. Especially so in combinationwith the object tracking manner disclosed in CF001SE.

Since a passive sensor requires much less power than a camera and alsothe controller controlling the input received from a passive lightenvironment sensor also requires less power, as the computations neededfor passive light environment sensor input control are less advancedthan for camera input control, the overall power consumption is reducedsignificantly during periods of touchless inactivity.

It is an object of the teachings of this application to overcome theproblems listed above by providing a portable device comprising acontroller, a memory, a camera and a passive proximity sensor, whereinthe controller is configured to receive input from said passiveproximity sensor indicating a light environment in front of the passiveproximity sensor, detect a change in light environment, determine alight pattern of changes in light environment, determine if the lightpattern matches a stored initiating pattern, which is stored in thememory, and if so, accept the light pattern and in response theretoactivate the camera, identify an object in front of the camera and trackthe object thereby enabling touchless gesture control of the portabledevice, characterized in that the passive proximity sensor is an ambientlight sensor and the light pattern consists of a series of changesbetween dark and light (dark is light below a threshold, light is lightabove a second threshold).

Such a portable device enables for an improved initiation of a touchlessgesture control as it reduces the power needed while still enabling theinitiation to be done in a touchless manner. The reason why the power isreduced is because the passive proximity sensor requires much less powerthan a camera and the recognition of a light changing pattern alsorequires less computing power (and hence less power) than therecognition of an object performing a gesture.

It should be noted that the use of a passive sensor requires much lesspower than an active sensors, such as cameras and can thus be used at avery low power cost while keeping the active camera deactivated—therebysignificantly reducing the power consumption of the device. The camerais not started unnecessarily, but only when there actually is a userthat wants to use the device.

It should further be noted that the inventors of this application hasrealized that also a sensor not originally designed for detecting amovement may be utilized for detecting a gesture, by a clever indirectmeasurement as disclosed herein.

It should also be noted that a light pattern is not to be equated with asimple change in light intensity, but would require distinct changes,such as either very sudden or preferably repeated changes.

In one embodiment, the portable device is a mobile communicationsterminal such as a tablet computer, a smartphone or a laptop computer.In one embodiment, the portable device is a game console. In oneembodiment, the portable device is a media device such as a music and/orvideo playing device.

It is also an object of the teachings of this application to overcomethe problems listed above by providing a method for use in a method foruse in a portable device comprising a controller, a memory, a camera anda passive proximity sensor, the method comprising receiving input fromsaid passive proximity sensor indicating a light environment in front ofthe passive proximity sensor, detecting a change in light environment,determining a light pattern of changes in light environment, determiningif the light pattern matches a stored initiating pattern, which isstored in the memory, and if so, accepting the light pattern and inresponse thereto activating the camera, identifying an object in frontof the camera and tracking the object thereby enabling touchless gesturecontrol of the portable device, characterized in that the passiveproximity sensor is an ambient light sensor and the light patternconsists of a series of changes between dark and light (dark is lightbelow a threshold, light is light above a second threshold).

It is a further object of the teachings of this application to overcomethe problems listed above by providing a computer readable mediumcomprising instructions that when loaded into and executed by acontroller, such as a processor, cause the execution of a methodaccording to herein.

The teachings herein find use in control systems for devices having userinterfaces such as mobile phones, smart phones, tablet computers, laptopcomputers, gaming consoles and media and other infotainment devices.

Other features and advantages of the disclosed embodiments will appearfrom the following detailed disclosure, from the attached dependentclaims as well as from the drawings. Generally, all terms used in theclaims are to be interpreted according to their ordinary meaning in thetechnical field, unless explicitly defined otherwise herein.

All references to “a/an/the [element, device, component, means, step,etc]” are to be interpreted openly as referring to at least one instanceof the element, device, component, means, step, etc., unless explicitlystated otherwise. The steps of any method disclosed herein do not haveto be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are schematic views of each a portable device accordingto the teachings herein;

FIG. 2 is a schematic view of the components of a portable deviceaccording to the teachings herein;

FIG. 3 is a schematic view of a computer-readable memory according tothe teachings herein;

FIGS. 4A, 4B and 4C each shows an example embodiment according to theteachings herein; and

FIG. 5 shows a flowchart illustrating a general method according to anembodiment of the teachings herein.

DETAILED DESCRIPTION

The disclosed embodiments will now be described more fully hereinafterwith reference to the accompanying drawings, in which certainembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided by way of example so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like numbers refer to like elements throughout.

FIG. 1 generally shows a portable device 100 according to an embodimentherein. In one embodiment the portable device 100 is configured fornetwork communication, either wireless or wired. Examples of a portabledevice 100 are: a laptop computer, a tablet computer, a mobilecommunications terminal such as a mobile telephone or a smart phone, apersonal digital assistant and a game console. Two embodiments will beexemplified and described as being a smartphone in FIG. 1A, a laptopcomputer 100 in FIG. 1B as an example of a computer and a tabletcomputer.

Referring to FIG. 1A a mobile communications terminal in the form of asmartphone 100 comprises a housing 110 in which a display 120 isarranged. In one embodiment the display 120 is a touch display. In otherembodiments the display 120 is a non-touch display. Furthermore, thesmartphone 100 comprises two keys 130 a, 130 b. In this embodiment thereare two keys 130, but any number of keys is possible and depends on thedesign of the smartphone 100. In one embodiment the smartphone 100 isconfigured to display and operate a virtual key 135 on the touch display120. It should be noted that the number of virtual keys 135 aredependant on the design of the smartphone 100 and an application that isexecuted on the smartphone 100. The smartphone 100 is also equipped witha camera 160. The camera 160 is a digital camera that is arranged totake video or still photographs by recording images on an electronicimage sensor (not shown). In one embodiment the camera 160 is anexternal camera. In one embodiment the camera is alternatively replacedby a source providing an image stream.

The smartphone 100 is further equipped with a passive proximity sensorpossibly being a passive light environment sensor 170. The passiveproximity sensor 170 is a sensor 270 as disclosed below with referenceto FIG. 2.

Referring to FIG. 1B a laptop computer 100 comprises a display 120 and ahousing 110. The housing comprises a controller or CPU (not shown) andone or more computer-readable storage mediums (not shown), such asstorage units and internal memory. Examples of storage units are diskdrives or hard drives. The laptop computer 100 further comprises atleast one data port. Data ports can be wired and/or wireless. Examplesof data ports are USB (Universal Serial Bus) ports, Ethernet ports orWiFi (according to IEEE standard 802.11) ports. Data ports areconfigured to enable a laptop computer 100 to connect with othercomputing devices or a server.

The laptop computer 100 further comprises at least one input unit suchas a keyboard 130. Other examples of input units are computer mouse,touch pads, touch screens or joysticks to name a few.

The laptop computer 100 is further equipped with a camera 160. Thecamera 160 is a digital camera that is arranged to take video or stillphotographs by recording images on an electronic image sensor (notshown). In one embodiment the camera 160 is an external camera. In oneembodiment the camera is alternatively replaced by a source providing animage stream.

The smartphone 100 is further equipped with a passive proximity sensorpossibly being a passive light environment sensor 170. The passiveproximity sensor 170 is a sensor 270 as disclosed below with referenceto FIG. 2.

FIG. 2 shows a schematic view of the general structure of a deviceaccording to FIG. 1. The device 100 comprises a controller 210 which isresponsible for the overall operation of the computing device 200 and ispreferably implemented by any commercially available CPU (“CentralProcessing Unit”), DSP (“Digital Signal Processor”) or any otherelectronic programmable logic device. The controller 210 is configuredto read instructions from the memory 240 and execute these instructionsto control the operation of the computing device 100. The memory 240 maybe implemented using any commonly known technology for computer-readablememories such as ROM, RAM, SRAM, DRAM, CMOS, FLASH, DDR, SDRAM or someother memory technology. The memory 240 is used for various purposes bythe controller 210, one of them being for storing application data andprogram instructions 250 for various software modules in the computingdevice 200. The software modules include a real-time operating system,drivers for a user interface 220, an application handler as well asvarious applications 250.

The computing device 200 further comprises a user interface 220, whichin the computing device of FIGS. 1A, 1B and 1C is comprised of thedisplay 120 and the keys 130, 135.

The computing device 200 may further comprises a radio frequencyinterface 230, which is adapted to allow the computing device tocommunicate with other devices through a radio frequency band throughthe use of different radio frequency technologies. Examples of suchtechnologies are IEEE 802.11, IEEE 802.15, ZigBee, WirelessHART, WIFI,Bluetooth®, W-CDMA/HSPA, GSM, UTRAN and LTE to name a few.

The computing device 200 is further equipped with a camera 260. Thecamera 260 is a digital camera that is arranged to take video or stillphotographs by recording images on an electronic image sensor (notshown).

The camera 260 is operably connected to the controller 210 to providethe controller with a video stream 265, i.e. the series of imagescaptured, for further processing possibly for use in and/or according toone or several of the applications 250.

In one embodiment the camera 260 is an external camera or source of animage stream.

The smartphone 200 is further equipped with a passive proximity sensor270. In one embodiment the passive proximity sensor 270 is a passivelight environment sensor.

A passive light environment sensor is a sensor 170, 270 arranged todetect the light environment in front of the sensor 170, 270. Thedetection is made passively, without actively sending, transmitting orradiating any signal or other waveform such as infrared light or otherlight types. The passive light environment sensor is only arranged todetect the light environment—i.e. to discern between light/dark(possibly in different degrees), not to make photographic captures. Oneexample of such a passive light environment sensor is an ambient lightsensor, ALS.

An ambient light sensor is a specific version of a photodiode. Aphotodiode is a type of photo detector capable of converting light intoa voltage or current, this depends on the mode of operation. A benefitof Ambient Light Sensors is that they perceive brightness in the sameway as human eyes do. Another benefit is that only require a minimum of(battery) power.

The passive light environment sensor is not designed to track an objectand to provide detailed light data. Only a reading on the ambient lightenvironment is provided by the passive light environment sensor.

The ALS is also not originally arranged to detect any movement ormotions. Only the ambient light level. Further more am ALS does notrequire additional hardware such as LED or an infrared light source.

The ALS is a preferred embodiment in that it is capable of detectinglight levels in fine grade, does not require additional hardwire, isalready implemented in many portable devices and thus allow for a simplesoftware update to enable a portable device to operate according to theteachings herein, and it does not add to the cost of making new portabledevices as they would most likely be equipped with an ALS for otherpurposes anyway. Furthermore the ALS has a superior power consumptionwhich is in line with the problem to be solved.

Other examples of passive proximity sensors are electrical, capacitiveand magnetic sensors arranged possibly not to detect the actual light infont of the sensor, but to detect a presence of an object in front ofthe sensor or possibly the distance to the object.

The inventors have realized though that the proximity to an or presenceof an object may used to be an equivalent to a light environment in thatdark equals close and light equals remote. For the purpose of thisapplication, the distance to or presence of an object to the sensor willthus indicate a light environment in front of the sensor. A proximitypattern is thus equal to a light pattern for the purpose of describingthe functionality of this invention.

It should also be noted that a light pattern is not to be equated with asimple change in light intensity, but would require distinct changes,such as either very sudden or preferably repeated changes.

It is important to note that the passive proximity sensor 170 is notoriginally arranged to detect and track an object for identifying agesture, it is only arranged to passively detect another physicalentity, such as light level or capacitance, but the input mayinventively be used to indirectly identify a gesture.

It is also important to note that such a sensor is possibly alsoenvisioned to be part of a portable device's finished design and the usethus does not add to the cost of the finished portable device. Thefunctionality may also be implemented in existing portable devicesalready equipped with such a sensor.

It should be noted that the use of a passive sensor requires much lesspower than the use of an active sensor such as a motion sensor and thatit requires inventive thought, as has been the case for thisapplication, to realize that the passive sensor may be used toindirectly function as a gesture detection means.

References to ‘computer-readable storage medium’, ‘computer programproduct’, ‘tangibly embodied computer program’ etc. or a ‘controller’,‘computer’, ‘processor’ etc. should be understood to encompass not onlycomputers having different architectures such as single/multi-processorarchitectures and sequential (Von Neumann)/parallel architectures butalso specialized circuits such as field-programmable gate arrays (FPGA),application specific circuits (ASIC), signal processing devices andother devices. References to computer program, instructions, code etc.should be understood to encompass software for a programmable processoror firmware such as, for example, the programmable content of a hardwaredevice whether instructions for a processor, or configuration settingsfor a fixed-function device, gate array or programmable logic deviceetc.

FIG. 3 shows a schematic view of a computer-readable medium as describedin the above. The computer-readable medium 30 is in this embodiment adata disc 30. In one embodiment the data disc 30 is a magnetic datastorage disc. The data disc 30 is configured to carry instructions 31that when loaded into a controller, such as a processor, executes amethod or procedure according to the embodiments disclosed above. Thedata disc 30 is arranged to be connected to or within and read by areading device 32, for loading the instructions into the controller. Onesuch example of a reading device 32 in combination with one (or several)data disc(s) 30 is a hard drive. It should be noted that thecomputer-readable medium can also be other mediums such as compactdiscs, digital video discs, flash memories or other memory technologiescommonly used.

The instructions 31 may also be downloaded to a computer data readingdevice 34, such as a laptop computer or other device capable of readingcomputer coded data on a computer-readable medium, by comprising theinstructions 31 in a computer-readable signal 33 which is transmittedvia a wireless (or wired) interface (for example via the Internet) tothe computer data reading device 34 for loading the instructions 31 intoa controller. In such an embodiment the computer-readable signal 33 isone type of a computer-readable medium 30.

The instructions may be stored in a memory (not shown explicitly in FIG.3, but referenced 240 in FIG. 2) of the laptop computer 34.

References to computer program, instructions, code etc. should beunderstood to encompass software for a programmable processor orfirmware such as, for example, the programmable content of a hardwaredevice whether instructions for a processor, or configuration settingsfor a fixed-function device, gate array or programmable logic deviceetc.

An improved manner of providing initiating a camera for receivingtouchless commands for touchless control of a device will be disclosedbelow with reference to the accompanying figures. The examples will beillustrated focusing on the gestures made and the resulting lightpatterns, but it should be clear that the processing is performed inpart or fully in a computing device comprising a controller as disclosedabove with reference to FIGS. 1 and 2 or caused to be performed byexecuting instructions stored on a computer-readable medium as disclosedwith reference to FIG. 3.

FIG. 4A shows an example portable device such as in FIG. 1, in thisexample a laptop computer 100 such as the laptop computer 100 of FIG.1B, configured to detect and track an object, in this example a hand H,via the camera 160. How such an object H is detected and tracked isdisclosed in the Swedish patent application SE 1250910-5 and will not bediscussed in further detail in the present application. For furtherdetails on this, please see the mentioned Swedish patent application. Itshould be noted, however, that the teachings of the present applicationmay be implemented through the use of other tracking manners thandisclosed in Swedish patent application SE 1250910-5.

To save power, the portable device 100 is arranged to turn off thecamera 160 when touchless input is not to be received. To further reducethe power consumption, the portable device 100 may be configured to turnoff the camera when a touchless input has not been identified orreceived within a threshold time period indicating inactivity.

However, to still allow a touchless control of the portable device 100,the portable device 100 is arranged with a passive proximity sensor 170,such as a passive light environment sensor 170. Such sensors 170 arecommonly found in prior art portable devices. However, the sensor 170 ofthe portable device 100 according to the teachings of the presentapplication is arranged, possibly in combination with the controller(referenced 210 in FIG. 2), to detect a movement pattern in front of thesensor and to identify a gesture from this movement and in responsethereto activate the camera 160 for receiving an image stream in whichobjects, such as a user's hand, may be tracked for touchless control.

A user uses his hand H or other object to perform a gesture in front ofthe sensor 170 which gesture is detected by the laptop 100 by detectinga light changing pattern P. To illustrate the functionality an exampleis given where a user moves his hand H from a position H1 at a distanceD1 from the laptop 100 to a second position H2 at a second, closerdistance D2 to the laptop 100.

As the hand is at position H2 the light environment in front of thesensor 170 has changed to darker compared to when the hand is atposition H1 as the hand H will block more light from reaching the sensor170.

In this example the user moves his hand H from H1 to H2, back to H1 andthen to H2 again and finally removes his hand (indicated by moving thehand back to H1 again). This movement pattern is illustrated with thearrows in FIG. 4A.

The movement pattern results in the sensor 170 being alternativelyshaded thus causing a light changing pattern to be generated. The lightchanging pattern corresponding to the movement pattern is illustrated asblack and white boxes in a series and referenced P in FIG. 4A. As can beseen in FIG. 4A the movement pattern generates the light changingpattern P “light/dark/light/dark/light”.

The controller matches the received light changing pattern to a storedpattern and if there is a match the controller 210 activates the cameraand the laptop 100 can be controlled in a touch less manner.

In other words (see the flowchart of FIG. 5), the controller 210 isconfigured to receive light input 510 from a passive light environmentsensor 170 indicating a light environment in front of the passive lightenvironment sensor and to detect a change 520 in the light environment.The controller further determines 530 a pattern of changes in lightenvironment, i.e. a light changing pattern and determines if the lightpattern P matches 540 a stored initiating pattern, which is stored inthe memory, and if so, accept the light pattern and in response theretoactivate 550 the camera 160, identify an object, such as the user's handH, in front of the camera 160 and track the object H thereby enablingtouchless gesture control of the portable device 100.

As has been discussed in relation to FIG. 2, the light pattern consistsof a series of changes between dark and light (dark is light below athreshold, light is light above a second threshold). Such changes arepreferably rapid—as would be the case if a user performed a gesture infront of the ALS—and not a gradual change—as would occur for example atdusk or at dawn.

In one embodiment the changes are in a time relation with each other.The changes may be in a time-relation to the full pattern and whereinthe controller is configured to buffer the detected light changes anddetect the light pattern by retro-checking the received light input.That is the light changes are buffered and parsed backwards fordetermining if a light pattern has been detected. The whole pattern hasto be buffered before a time frame can be established for determining ifthe time relation is fulfilled or not for the pattern.

In another embodiment the controller is determined to determine that achange happens within a time period. For example, the light/dark/lightof a push gesture should be so that each segment is less than 0.3 s andthat the total sequence is less than 0.5 s.

In one embodiment the controller is configured to determine that a lightchange in a sequence has approximately the same time extension as theaverage of the other changes in the light sequence.

It should be noted that the time relation of a time change may relate tothe time it actually takes to change from one light condition to anotheror to the time for each light environment state.

In one embodiment the controller is further configured to determine adirection in which a change in light occurs and wherein the lightpattern further consists of the directions of the light changes. Theexample of FIG. 4B shows an example of such a pattern.

In one embodiment, the controller is further configured to prompt for aconfirmation and detect a confirmation light pattern and determine ifthe confirmation light pattern indicates a confirmation and if so acceptthe light pattern.

A confirmation light pattern may be a push pattern (that islight/dark/light) or a repeat of the detected light pattern. The latterenables more advanced control. Using a repeat of the pattern is highlyuseful if the pattern is a simple pattern—or it becomes cumbersome toinput a long range of patterns.

The prompt may be displayed on the display 120, possibly as a popupwindow, instructing the user to perform the confirmation input.

The prompt may also or alternatively be an audible prompt instructingthe user to perform the confirmation input.

The portable device 100 may also be arranged with a movement sensor (notshown), such as an accelerometer or gyro (not shown). Such movementsensors are commonly found in portable devices and thus also do notrequire any modification to the hardware of a portable device.

In one embodiment the controller is configured to receive movement inputfrom the movement sensor and determine if the portable device is movingor not while detecting the light pattern. If it is determined that theportable device is not moving the detected light pattern most likely isa consciously effected light pattern originating from a gesture and thepattern is accepted and the camera is activated.

In one embodiment the controller is further configured to prompt for aconfirmation if it is detected that the portable device is moving whiledetecting the light pattern.

In one embodiment the controller is further configured to determine ifthe detected movement constitutes a moving pattern and if the movingpattern matches the light pattern. If so the light pattern is mostlikely a result of the movement and it is discarded, or the controllerprompts for confirmation.

The movement pattern can be matched to the light pattern by comparingchanges in direction with changes in light. If there is a correspondencethere could be a match between the two patterns.

FIG. 4B shows an example computing device such as in FIG. 1, in thisexample a laptop computer 100 such as the laptop computer 100 of FIG.1B, configured to detect and track an object, in this example a hand H,via the camera 160. In this example the laptop 100 is arranged with asensor 170 which is able to detect in what direction the light changes(for example, from left to right). This enables for other movementpatterns to be used. To illustrate the functionality a second example isgiven where a user moves his hand H from left to right and back again ata distance D from the laptop 100. This movement pattern is illustratedwith the arrows in FIG. 4B.

As the hand H passes the sensor 170, the sensor 170 is first partiallyblocked, blocked, partially blocked and finally not blocked again.

The movement pattern results in the sensor 170 being alternativelyshaded thus causing a light changing pattern to be generated. The lightchanging pattern corresponding to the movement pattern is illustrated asblack and white boxes in a series and referenced P in FIG. 4B. Thesensor is able to determine that the partial blocking is on a left orright side respectively thereby generating a partial light box in thelight changing pattern. As can be seen in FIG. 4B the movement patterngenerates the light changing pattern P “light/half dark left/half darkright/dark/half dark left/half dark right/light/half dark right/halfdark left/dark/half dark right/half dark left/light”.

After recognizing the light changing pattern the camera 160 is activatedand the laptop can be controlled in a touch less manner.

In one embodiment the portable device is arranged with more than onesensor 170. The use of multiple sensors 170 enables for detecting a morecomplex pattern in that angles to an object may be determined.Furthermore, movement patterns may be more easily identifiable.

FIG. 4C shows an example of a portable device 100 having two sensors 170a and 170 b. An object, such as a hand H, is placed in front of theportable device 100. As an example of a gesture, the hand H is movedfrom one position H1 in front of the first sensor 170 a to a secondposition H2 in front of the second sensor 170 b and back again. Theresulting pattern P is detected as two sub-patterns Pa and Pb for thefirst and the second sensor 170 a and 170 b respectively. As can be seenPa is dark/light/dark and Pb is light/dark/light. The two sub-patternsare, in one embodiment, timed with each other so that the patternchanges occur at approximately the same time or even overlapping.

The teachings herein provide the benefit that a user is able to initiatethe touchless interface with a touchless command and not having toactually activate a special key or other manual input means, while theapparatus is able to reduce its power consumption as the camera 160 doesnot need to be active waiting to detect a gesture.

The invention has mainly been described above with reference to a fewembodiments. However, as is readily appreciated by a person skilled inthe art, other embodiments than the ones disclosed above are equallypossible within the scope of the invention, as defined by the appendedpatent claims.

1-15. (canceled)
 16. A portable device (100) comprising a controller(210), a memory (240), a camera (160) and a passive proximity sensor(170), wherein the controller is configured to: receive input from saidpassive proximity sensor (170) indicating a light environment in frontof the passive proximity sensor (170); detect a change in lightenvironment; determine a light pattern (P) of changes in lightenvironment; determine if the light pattern matches a stored initiatingpattern, which is stored in the memory (240), and if so, accept thelight pattern (P) and in response thereto activate the camera (160),identify an object (H) in front of the camera (160) and track the object(H) thereby enabling touchless gesture control of the portable device(100), characterized in that the passive proximity sensor (170) is anambient light sensor and the light pattern (P) consists of a series ofchanges between dark and light (dark is light intensity below athreshold, light is light intensity above a second threshold).
 17. Theportable device (100) of claim 16, wherein the passive proximity sensoris configured to detect a presence of an object and the light pattern isa proximity pattern.
 18. The portable device (100) of claim 16, whereinthe changes are in a time relation with each other.
 19. The portabledevice (100) of claim 16, wherein the changes are in a time-relation tothe full pattern and wherein the controller (210) is configured tobuffer the detected light changes and detect the light pattern byretro-checking the detected light changes.
 20. The portable device (100)of claim 16, wherein the controller (210) is configured to determine adirection in which a change in light occurs and wherein the lightpattern (P) further consists of the directions of the light changes. 21.The portable device (100) of claim 16, wherein the controller (210) isfurther configured to prompt for a confirmation and detect aconfirmation light pattern and determine if the confirmation lightpattern indicates a confirmation and if so accept the light pattern (P).22. The portable device (100) of claim 16, further comprising a movementsensor and wherein the controller (210) is configured to receivemovement input from the movement sensor and determine if the portabledevice (100) is moving or not while detecting the light pattern, and ifthe portable device (100) is not moving, the pattern is accepted. 23.The portable device (100) of claim 22, wherein the controller (210) isfurther configured to prompt for a confirmation if it is detected thatthe portable device (100) is moving while detecting the light pattern(P).
 24. The portable device (100) of claim 22, wherein the controller(210) is further configured to determine if the detected movementconstitutes a moving pattern and if the moving pattern matches the lightpattern (P), and if there is a match discard the light pattern (P) orprompt for confirmation.
 25. The portable device (100) of claim 16,further comprising a second passive proximity sensor (170 b) and whereinthe pattern (P) comprises at least two sub-patterns (Pa, Pb), onesub-pattern for each passive proximity sensor (170 a, 170 b).
 26. Themobile communications terminal of claim 25, wherein the at least twosub-patterns (Pa, Pb) are timed with each other so that the patternchanges occur at approximately the same time or are overlapping.
 27. Theportable device (100) of claim 16, wherein the portable device (100) isa mobile communications terminal.
 28. The mobile communications terminalof claim 27, wherein the mobile communications terminal is a mobilephone.
 29. A method for use in a portable device (100) comprising acontroller (210), a memory (240), a camera (160) and a passive proximitysensor (170), the method comprising: receiving input from said passiveproximity sensor (170) indicating a light environment in front of thepassive proximity sensor (170); detecting a change in light environment;determining a light pattern (P) of changes in light environment;determining if the light pattern (P) matches a stored initiatingpattern, which is stored in the memory (240), and if so, accepting thelight pattern (P) and in response thereto activating the camera (160),identifying an object (H) in front of the camera (160) and tracking theobject (H) thereby enabling touchless gesture control of the portabledevice (100), method being characterized in that the passive proximitysensor (170) is an ambient light sensor and the light pattern (P)consists of a series of changes between dark and light (dark is lightintensity below a threshold, light is light intensity above a secondthreshold).
 30. A computer readable storage medium (30) encoded withinstructions (31) that, when loaded and executed on a controller of aportable device (100, 200), causes the method according to claim 29 tobe performed.
 31. The portable device (100) of claim 17, wherein thecontroller (210) is configured to determine a direction in which achange in light occurs and wherein the light pattern (P) furtherconsists of the directions of the light changes.
 32. The portable device(100) of claim 18, wherein the controller (210) is configured todetermine a direction in which a change in light occurs and wherein thelight pattern (P) further consists of the directions of the lightchanges.
 33. The portable device (100) of claim 19, wherein thecontroller (210) is configured to determine a direction in which achange in light occurs and wherein the light pattern (P) furtherconsists of the directions of the light changes.
 34. The portable device(100) of claim 17, wherein the controller (210) is further configured toprompt for a confirmation and detect a confirmation light pattern anddetermine if the confirmation light pattern indicates a confirmation andif so accept the light pattern (P).
 35. The portable device (100) ofclaim 18, wherein the controller (210) is further configured to promptfor a confirmation and detect a confirmation light pattern and determineif the confirmation light pattern indicates a confirmation and if soaccept the light pattern (P).